- From: Ben Maurer <bmaurer@andrew.cmu.edu>
- Date: Tue, 17 Jul 2007 10:10:11 -0700 (PDT)
- To: "Gregory J. Rosmaita" <oedipus@hicom.net>
- cc: wai-xtech@w3.org, Al Gilman <Alfred.S.Gilman@IEEE.org>, Colin McMillen <mcmillen@cs.cmu.edu>
Hey, On Tue, 17 Jul 2007, Gregory J. Rosmaita wrote: > aloha, all! > > concerning the cascade of aural CAPTCHA equivalents, i have pondered > the issue of baseline audio formats for quite some time, but can't > find the post i was preparing on the topic, so i'll just simply ask: > what is the cascade order for aural filetypes in the real world > today? > > .ogg > .mp3 > .au AFAIK, no brwoser has support for a cascade like this. Doesn't make that topic somewhat moot. > 1) is .au the baseline for web delivered audio content? .wav would be a good baseline. We initially considered serving up .wav reCAPTCHAs, however: 1. Bandwidth was potentially prohibitive (25 KB mp3 vs 250 KB wav) 2. Disk space was also prohibitive 3. mp3 was universal enough for us. > 2) is .ogg widely enough supported to retain first place in the cascade? There's no support for ogg in default windows and mac installs. > > 4) are .mp3 files capable of being played using the user agent or > operating system's default sound renderer? AFAIK, all audio files are played by browsers with support of plugins. Ogg, mp3 and wav are equal in this sense. > has any thought gone into serving up pure sounds (dog bark, duck quack, > train whistle) to defeat the voice-recognition? this would involve a > quick lookup for the appropriate answer in lang="x" or, through > content negotiation serve up a version of the CAPTCHA that corresponds > to the requesting user agent's language preferences, which would make > the verification look-up faster... Some issues here: - WE would still need quite a bit of distortion & background noise - There are multiple answers (dog barking -- bark, dog, dog bark, woof) - If multi-word answers are used, segmentation of the answers becomes hard. - Much harder to translate - Need to do spelling correction - Requires better understanding of language at hand - Need to acquire a large number of sounds. -b
Received on Tuesday, 17 July 2007 17:10:32 UTC